Solid electrolytic capacitor

Abstract

A hybrid-type solid electrolytic capacitor which suppresses corrosive reaction even if chlorine ions are contaminated while suppressing deterioration of product characteristics. The solid electrolytic capacitor includes a capacitor element including an anode foil and a cathode foil facing each other and an electrolyte layer formed in the capacitor element. The electrolyte layer includes a solid electrolyte layer including a dopant and a conjugated polymer, and an electrolyte solution filled in air gaps in the capacitor element on which the solid electrolyte layer is formed. The electrolyte layer includes a cation component at a molecular ratio of 6 or less relative to 1 mol of a functional group which can contribute to a doping reaction of the dopant, and the electrolytic solution includes a sulfolane-based solvent.

The invention claimed is: 
     
       1. A solid electrolytic capacitor comprising:
 a capacitor element including an anode foil and a cathode foil facing each other; and 
 an electrolyte layer formed in the capacitor element, 
 wherein: 
 the electrolyte layer includes: 
 a solid electrolyte layer including a dopant and a conjugated polymer; and 
 an electrolyte solution filled in air gaps in the capacitor element on which the solid electrolyte layer is formed, 
 the electrolyte layer includes a cation component, 
 the cation component is included at a molecular ratio of more than 0 and 6 or less relative to 1 mol of a functional group which can contribute to a doping reaction of the dopant, and 
 the electrolytic solution includes a sulfolane-based solvent. 
 
     
     
       2. The solid electrolytic capacitor according to  claim 1 , wherein the electrolyte layer includes aliphatic carboxylic acid in which a carbon number of a main chain is 4 or more as an anion component. 
     
     
       3. The solid electrolytic capacitor according to  claim 2 , wherein the cation component is included at the molecular ratio of 3.5 or less relative to 1 mol of the functional group capable of contributing to the doped reaction of the dopant. 
     
     
       4. The solid electrolytic capacitor according to  claim 2 , wherein the aliphatic carboxylic acid may be azelaic acid. 
     
     
       5. The solid electrolytic capacitor according to  claim 4 , the cation component is included at the molecular ratio of 1.4 or less relative to 1 mol of the functional group capable of contributing to the doped reaction of the dopant. 
     
     
       6. The solid electrolytic capacitor according to any one of  claims 2 to 5 , wherein the anion component is included at an equimolar amount to the cation component. 
     
     
       7. The solid electrolytic capacitor according to any one of  claims 1 to 5 , wherein:
 the electrolytic solution includes ethylene glycol together with the sulfolane-based solvent, and 
 a mixing ratio of the sulfolane-based solvent relative to a total amount of the sulfolane-based solvent and the ethylene glycol may be 25 wt % or more. 
 
     
     
       8. The solid electrolytic capacitor according to any one of  claims 1 to 5 , wherein the sulfolane-based solvent is at least one selected from sulfolane, 3-methyl-sulfolane, and 2,4-dimethyl-sulfolane. 
     
     
       9. The solid electrolytic capacitor according to any one of  claims 1 to 5 , wherein the solid electrolyte layer includes sorbitol. 
     
     
       10. The solid electrolytic capacitor according to  claim 1 , wherein the cation component is included at the molecular ratio of 0.4 or more and 6 or less relative to 1 mol of the functional group capable of contributing to the doped reaction of the dopant.